Lifeless ice? At first glance, the cryosphere – including all frozen water on Earth – appears to comprise vast, cold expanses devoid of biology. However, even the most remote, hostile and unlikely icy locations in both hemispheres have been found to harbour diverse and active microbial life. It is hard to imagine ice offering many viable places for microbes to exploit; but liquid water and energy sources exist beneath, within, and especially on the surfaces of glaciers and ice sheets. Research has shown us that not only are ice-dwelling microbial communities crucial stores of biodiversity, they might be important amplifiers of global climate change. The area...

The rainforest is burning in Sumatra, Indonesia. A majestic Meranti tree is close to the fire line. As flames from the surrounding canopy rage closer to this ancient tree, water quickly evaporates from its leaves, transforming the foliage into dry fuel for the fire. When turbulent, convective winds within the canopy bring hot air to the immediate surroundings of our tree, long-chain cellulose molecules in the desiccated foliage begin to crack, producing hydrocarbon gases and solid char deposits; with a flash, the gases ignite, forming the flames of the fire. This brief, catastrophic episode at the end of this tree’s life quickly re-balances a century...